PSP downloadable titles are playable on the vita. PS minis are playable on ps3 and vita.
There's also the issue of cross play titles (PS all star battle royale, wipeout, SF x Tekken, Retro City Rampage) and "free" games that you are supposed to be able to access as long as you keep up your subscription.
NOT including PS3 compatibility breaks the hell out of PSN. Cross play no longer works, existing minis won't work, and free titles you're paying a yearly subscription to keep access to no longer work.
it's a bad move.
You will have access to those titles all the time you have a PS3. That is exactly what you paid for. They don't magically stop working because you bought a PS4.
PSN game does not = PS3 game. PSN game just means "Game not sold at retail". There are loads of "PSN" games that are on the PS Vita that I also can't play on my PS3. They are Vita games, not "PSN" games.
Can you play any of the PS3 PSN titles you listed on any other device other than a PS3? They were sold as PS3 games that you bought over the PSN Network. As are retail games which you can download over the PSN network. They were never marketed as anything else.
Minis will still work just fine even without BC, they don't access the low level PS3 power because they also run on the PSP and the Vita.
Now, they
should include BC so that you can still access that content however they are not obliged to in any way. You bought that content for the PS3, you got PS+ content for the PS3, you will always be able to play that content on a PS3.
As I have said before, I don't
really care if I can play PS3 games on my PS4. If it's there then great, if not then I'll still buy a PS4 regardless. No fucks shall be given. But they should include it if it is possible, technologically and financially.
From their point of view being able to leverage every PS1,PS2 & PS3 title on one device would create a library accessible on one device that is probably unparalleled. People will still buy PS1 and PS2 games on it. Of that I have no doubt.